Installing Hardwood Floor over Concrete

I have always loved hardwood floors and would like to have one in my dining room. I finally convinced my husband to install this, but I can't seem to find the information on how to install this over cement. A list of products needed and a simple how to guide would be wonderful.

We have installed slate, ceramic, a paver patio and a fence on our own, we have the time and inclination, I just want to do it right the first time.

You can absolutely install a wood floor over concrete if you fulfill 2 preparation steps:

1/ Install a flexible water membrane .. must spread 2 coats that cross each other.

Sold at home depot.

2/ Then instal (Glue / Nail) a wood based underlayment 4 by 8 panels (eg. 4 mm Luan wood is the minimum or 1/2 inch PT or OSB to comply to code possibly / Pressure Treated is bad for your health if good for your floor ... cannot be in contact with human habitat.) must be anchored/glued to the concrete slab on top of the waterproof membrane.

Available at home depot

basically you transform you slab into a beam foundation with 4 by 8 PT or OSB

FYI: Float the floor if too uneven ...

Home depot: self leveling.

Make sense. It is not because someone does not know that it cannot be done. Just find those we know and who did it.

If you do not want to glue it, then take 3/4 inch thick plywood (thicker to allow nail with tongue and groove) and nail your wood floor to it. FYI: Across the panels rather than parrallell.

It is a very simple thing to do. Just the nail fun for wood floor is expansive but you can rent for a couple of days.

Of course a contractor will charge you a fortune to get it done ... but nowadays noone works a day work for less than $500. Gas and lunch are expansive nowadays!

I really love the look and feel of hardwood floors, I just moved into a new place and am lucky to have them as a floor!

Installing solid hardwood floors over concrete can be done, but honestly, it's something that I would strongly NOT recommend your husband to install. The main reason is due to the expansion of the wood; it's a natural product that breathes and flexes slightly even after installed. The issue you would run into would be that you would need to glue the solid plank wood to the concrete, which won't allow for hardly any expansion and contraction, and over time you can see some planks possibly warping or popping up. Which that maybe the reason you could find little to no information on installing it over concrete, it's just something that flooring installers typically don't do.

Now, that was the bad news...The good news is you can still put down a real wood floor!

How?

Simply purchase a engineered floor or click-lock flooring planks in real wood! For years, the only thing out on the market when it came to hardwood floors was solid (one-piece) planks. Now you also have the options of placing down an engineered or click-lock floor for your dining room!

The reason why you would need to choose these systems over solid hardwood is because since you are dealing with a concrete subfloor, the layers of wood that are assembled and glued together in click-lock and engineered systems will tolerate and give the stronger floor that will not give way over hardwoods.

To see the differences between engineered and floating, or click-lock systems, refer to the picture below for a better exploitation...

Since you guys have already installed all sorts of tile and even a fence, this project should be a breeze!

Remember that both engineered and click-lock flooring will give you the look of real wood because it IS real wood! It just depends on if you want to glue the engineered flooring systems down or use a cushioned underlayment and put down the glue-free click-lock planks, it is entirely up to you.

In terms of installation, engineered floors that are going to be glued down act the same exact way of install steps as solid hardwood pieces. Start at the longest uninterrupted wall, and proceed to start out your first row of flooring, starting with a long plank, although some engineered floors have the same plank lengths. Keep about a 1/4" inch or so away from the wall to allow for the slight expansion of the wood, even though it will be glued down. You'll need to mix and create a pattern that you like ahead of the install planks by placing them before they are glued on the floor to get an idea of what you want from the final floor. This is called "racking the boards". The glue can get messy, but you'll still need a good tapping block and hammer to drive the planks in place. In terms of the glue to use, you will need one with a urethane-based adhesive so as to allow the moisture from the concrete to be blocked by the glue. The glue I would recommend we sell in our flooring department and looks like the one below...

If the thought of glue and getting gunk all over the floor doesn't entice you, you can get the same moisture-proofing

results from installing a click-lock flooring with a moisture barrier underlayment that was shown in the picture above.

And the best part is is that it install exactly like a laminate flooring systems, but with the look and feel of real wood!

For detailed installation instructions, you can find the how-to video of how to install it off of our website, which can be found by clicking here!

Hopefully Lynn, this will get you on your way to decide what the best way to get real wood down in your dining room.

Thanks, but no thanks. I don't like the engineered floors. I have been looking for a long time and found only the hardwood is suitable. If it can't be done, then I'll find a way. I know people who have done it, it didn't involve glue and I will go to them.

Thank you so much. I knew it could be done, just didn't know how. Really appreciate the input. I don't mind gluing the floor, just thought it was silly to glue it to a concrete slab. Wouldn't keep it dry enough or flexible enough.

You can absolutely install a wood floor over concrete if you fulfill 2 preparation steps:

1/ Install a flexible water membrane .. must spread 2 coats that cross each other.

Sold at home depot.

2/ Then instal (Glue / Nail) a wood based underlayment 4 by 8 panels (eg. 4 mm Luan wood is the minimum or 1/2 inch PT or OSB to comply to code possibly / Pressure Treated is bad for your health if good for your floor ... cannot be in contact with human habitat.) must be anchored/glued to the concrete slab on top of the waterproof membrane.

Available at home depot

basically you transform you slab into a beam foundation with 4 by 8 PT or OSB

FYI: Float the floor if too uneven ...

Home depot: self leveling.

Make sense. It is not because someone does not know that it cannot be done. Just find those we know and who did it.

If you do not want to glue it, then take 3/4 inch thick plywood (thicker to allow nail with tongue and groove) and nail your wood floor to it. FYI: Across the panels rather than parrallell.

It is a very simple thing to do. Just the nail fun for wood floor is expansive but you can rent for a couple of days.

Of course a contractor will charge you a fortune to get it done ... but nowadays noone works a day work for less than $500. Gas and lunch are expansive nowadays!

Et Voila:

Done it!

Anything Else.?

@Lynn thanks for your questions and welcome to the How-To-Community.

@Lucf merci beaucoup for your great response!

I have to say this is an excellent read if you are looking for the step by step instruction on how to install solid flooring over concrete slab-this is the thread to read.

Although there are some things here that I disagree with a little (peu) bit...:smileyhappy:

First let’s go back here and simplify this a little bit and answer some of the questions asked;

Can it be done?

YES it CAN. I agree with lucf solid hardwood CAN absolutely be installed over concrete and there is more than one method that can be done with.

Should we always install solid hardwood flooring over a concrete slab ;NO.

Most manufacturers out there will not warranty their product if ;

Solid flooring is getting installed over newly poured slab, within 60 days

If the (RH) relative humidity " target="_blank">testings for concrete moisture content are higher than 75 -80%

If the flooring was not room conditioned prior to installation

Polyethylene test was not performed

Now going back to the first step in the quoted response;

1/ Install a flexible water membrane .. must spread 2 coats that cross each other.﻿

Water membrane it’s not a product that is used to reduce moisture permeability from the concrete slab.

Most slabs, per code, already have something called Vapor Retardant (4mill-6mill) installed to block moisture and in some instances radon gases from the soil bellow.

Your slab may not even need additional vapor barrier, that’s why polyethylene test should be performed.

Basically you would tape a piece of clear plastic film to the slab and place a lamp over it. After 24 hrs if no condensation develops floor can be considered dry and ready for installation.

If condensation does occur than urethane base vapor barrier should be applied. See attached product images;

I’m assuming lucf; this is what you were referring to?

2/ Then instal (Glue / Nail) a wood based underlayment 4 by 8 panels (eg. 4 mm Luan wood is the minimum or 1/2 inch PT or OSB to comply to code possibly / Pressure Treated is bad for your health if good for your floor ... cannot be in contact with human habitat.) must be anchored/glued to the concrete slab on top of the waterproof membrane.

Available at home depot

Only pressure treated lumber is approved, per code, to be used in applications with direct ground contact.

This said installing CDX, CDX TG, OSB,BC plywood or Moisture repellant Luan in direct contact with concrete slab would not be advisable, in my opinion. Over time mold and rot could occur (room temperature changes) in between plywood and subfloor void.

Now researching your project you will find online that there are installers that use felt paper to resolve this issue in between plywood and concrete leaving perimeter gap for moisture to escape, not a best practice again in my opinion.

Pressure Treated is bad for your health if good for your floor ... cannot be in contact with human habitat.) must be anchored/glued to the concrete slab on top of the waterproof membrane

" target="_blank">Pressure treated is rated to be used in direct contact with concrete it is treated to resist rot and decay and I see no need to be placed over any kind of membrane.

Years back actually arsenate (CCA) was used in treating process nowadays that’s no longer a case and ACQ water base preservative is used. It is still advisable to use respiratory protection when cutting treated lumber.

Note that also only hot dipped galvanized fasteners can be used with PT lumber.

basically you transform you slab into a beam foundation

Correct, best method to be used when framing a nailing subfloor over concrete slab is to place sheathing over something we call in trades “sleepers”.

What are “sleepers”? Sleepers are dimensional pressure treated lumber that are fastened down every 16” over concrete slab and vapor barrier (if needed) and are there to serve as a support for subfloor grade plywood.

Some installers place XPS (extruded polystyrene) foam sheets in between sleepers to provide additional moisture barrier (0.5 perm rating) and add insulating value to the floor.

@Lynn this is your best option if you are looking to nail down your floor over concrete slab, in y opinion.

Although you have to keep in mind that this will raise your floor and that you may have to make some adjustments around door openings.

I noticed that you said you love solid hardwood floors; so we know what the decision is :smileyhappy:

My recommendation would be to glue your floor down directly to concrete following these steps;

Measure moisture content of the subfloor; assure that humidity is lower than 75%

I know this thread is old, but we covered our concrete floors with kraft brown paper. We tore random shapes/pieces and glued to the concrete with a water/glue solution. After it dried, we covered the floor with polyurethene. We let it dry out completely before moving in. Now, eight years later, some of the flooring is coming up because of the uneven floor space created pockets under the paper and heels or chair legs have cracked it.

My question is if we want to cover in hardwood as you described, what extra steps would be needed to address the paper/polyeurethene currently on the floors. Thanks in advance.

I've heard of using builder's paper in this kind of situation, but it sounds like due to the unevenness of the floor as you stated as well as the water/glue solution possibly breaking down, led to where we are now.

As I mentioned earlier in the thread, you can use other real-wood systems like engineered or click-lock to achieve the look you want. In the case of click-lock, it simply floats over the surface while using an attached underlayment. However, any imperfections and unevenness of the existing concrete floor needs to be addressed. In fact, whenever any new flooring is being installed, the existing subfloor has to be free of debris, clean, and even.

How? By first taking off the layers of paper by a floor and/or hand scraper. If the concrete floor is fairly smooth, using a floor scraper shown below is a great start to getting most of the paper off the floor.

For harder to scrape off or smaller areas, you can use the smaller hand-held 4 inch counterpart as well. Using knee pads at this step will greatly help you out.

After scraping off the paper, you still may have adhesive and polyurethane still left over. To get rid of this, follow the steps on a recent post I did for removing adhesive off a concrete floor. Clicking on the image below will take you to it.

After following those steps in the link above, you can now cover your concrete subfloor with any wood covering of your choice. If it is solid hardwood, follow SteelToesinformation in this thread. To make the hardwood suitable for concrete you can also refer to my post on how to install solid hardwood floors over concrete. Click on the diagram below to find out more...

And lastly, if you would like to view install information on other types of real wood flooring, like click-lock or engineered, please refer to my first response on this thread.

I hope this has helped you, and please let us know if you have any further questions.

george - u r so right! my wife and i put engineered flooring on concrete - we did all the tests needed. leveleled where needed. even bought a laser meter to make sure the temp of the slab was warm enough for install. we, used way too much glue & even glued the (tongue n' groove parts) which has made it stay completely in place for over 4 years. no cupping - no popping. now, if we ever have to take it out - i'll definatlely contract that part out. it was a pretty messy job & seemed to take us forever to do but, pretty happy with the whole thing.